I had a crash when generating out from the above mentioned version of ScanTailor. At first, I aimlessly changed the content box on the page it crashed and i helped. Then, that didn't help so I decide to try debugging.
Compiled with Debug, and run through gdb. Assert failure in the OutputGenerator constructor, line 253
I'm very c++-rusty, so crude printing of the coordinates for m_outRect and _contentRect showed that contentRect when it crashed was one more than outRect. Looked a couple of lines above, and saw the creation of these members came from resultingRect() and boundingRect(). Immediately suspected rounding errors and changed the ".toRect()" on lines 247 and 248 to ".toAlignedRect()".
Voila, Works For Me!
Perhaps one should do a more thorough analysis than my stabs in the dark before committing to code...